In the Dungeons & Dragonsfantasyrole-playing game, the howler is an outsider from planes dominated by evil forces, e.g... the lower planes. It resembles a furless monkey crossed with a sickly dog, and has a vaguely human-like face. It is grey in color, with the slightest hints of violet. For no apparent reason, its shoulders jut sharply up in ugly extremities. Growing along its back and from its front legs, are sharp quills.

The howler, as its name suggests, spends the time when it isn't hunting howling. The eerie, resonating noise causes anyone who hears it for an extensive amount of time to go mad. When hunting, the howler travels in packs. It is a cruel and cowardly creature, so it is rarely found alone. They attack prey by charging in, then leaving again, then charging back, and so on. They cause damage in this method by thrashing about and scratching prey with their sharp quills. Occasionally, they might also bellow a particularly focused howl in the victim's face.

Howlers, strangely, are sometimes valued and trained as mounts. Taming one requires that the howler has a friendly attitude towards the rider/tamer, and being evil creatures, the rider must be of evil or neutral alignment himself. Although they are not flying mounts such as pegasi and giant eagles, riding one requires the customary exotic saddle and 6 weeks of training.

Howlers cannot speak, but understand Abyssal (they are surprisingly intelligent). Some believe there to be a Howler unique language in the howls, but it cannot be deciphered.